public class Circle {
    private double radius;
    
    public Circle() {
    }
    
    public Circle(double radius) {
        this.radius = radius;
    }
    
    public void setRadius(double radius) {
        this.radius = radius;
    }
    
    public double getRadius() {
        return radius;
    }
    
    public double getPerimeter() {
        double perimeter = 2 * Math.PI * radius;
        return Math.round(perimeter * 100.0) / 100.0;
    }
    
    public double getArea() {
        double area = Math.PI * radius * radius;
        return Math.round(area * 100.0) / 100.0;
    }
    
    public void display() {
        System.out.println("周长: " + getPerimeter() + ", 面积: " + getArea());
    }
}

